I did have to send it in when it started blowing fuses upon power-up (had nothing to do with the upgrade, according to Yorkville), but they sent another at no cost to me. Hopefully it was just an aberration - the new one is cranking away just fine.

The tone is quite good - warm, tubey, about what you'd expect. The phrase "SVT-ish" comes to mind.

Wouldn't use it in anything larger than a medium-sized room, though, even with my Schroeder. It wouldn't keep up.

I was wondering what was considered a medium sized room. I play in a band with 2 loud guitarists and a loud drummer, do you think I should have trouble being heard if I paired this with the 8x8 yorkville? That's supposed to create a big svt stack type sound. Thanks.

I was wondering what was considered a medium sized room. I play in a band with 2 loud guitarists and a loud drummer, do you think I should have trouble being heard if I paired this with the 8x8 yorkville? That's supposed to create a big svt stack type sound. Thanks.

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Hmmm..... I use it with a Schroeder 21012, which is regarded as being very sensitive/efficient (probably more so than the Yorkville you mentioned).

And I wouldn't be comfortable bringing it to a room the size of your average high school gymnasium, for example.

I think it would be louder than the amps you mentioned, depending on which 212 you are using. However, I wouldn't pair it with the 808. Try it out yourself and if thats your thing then get it. However, I would try using it with a 212 or 410, or both or one or the other paired with a 115. You could try it with the SWR 8x8 if you really want 8s, but I don't like the Yorkville 808.

When I was buying my NV610, I tried it with a YBA-200 and it sounded fantastic. But I wouldn't ever take one to a rock gig with that cab, at least not a stock YBA-200. It just didn't have enough juice to back a drummer who hit moderately hard. If I picked one up it would be more of a studio amp than anything.

I had one and performed the preamp tube swap to a pair of 12AY7's and it still didn't have enough clean headroom. Plus my Warwick overdrove the preamp section no matter how low the gain was on both amp and bass, at gig volumes that is and in the bedroom it wasn't much better. Good amp, sounded way better with new tubes but not enough headroom. I think Traynor would have had a surefire winner on their hands if they'd set the amps' natural gain lower.

You can take the YBA 200 to a rock gig. It will stand up decent so long as you don't have stock tubes, but if your band is real loud then you may need something more. However, it will stand up to a loud drummer and a Marshall halfstack as long as you are playing at an acceptable (fairly loud but not screaming) volume. With the right cab and tubes you can probabally even play screamingly loud, but you would be pushing it to its limits. No headroom at all, a good amount of overdrive which approaches distortion... It is a great amp but for larger gigs you will need a bit more juice if you don't plug into the PA.

With tw0 12at7s in the pre amp and KT88s in the power section I have lots of clean headroom...maybe a little too much, I am thinking of going with a 12ax7 in V2 to increase the gain a bit more and get more OD from the power tubes.

Yes it made a big diffrence in headroom and a noticebale diffrence in tone. The mids seem to shine more and the lows are more defined...I let Turlu, another Talkbass member, borrow my YBA200 after the modifications, and he finds that there is a big diffrence between my amp and the stock YBA200 that he tried at the store. He is now considering going with a YBA200 instead of his XS800H...

What brand KT-88 did you go with? I've heard good things about the recent Valve Art production.

I'm trying a quad of their KT-66 for my Bassman, and am thinking of their 2A3 for a "boat anchor" Hammond field coil amp modification project (4x 2A3 in push/pull, driven by a pair of 56, tube rectified with 5U4). It might make a kool amp for recording.

What brand KT-88 did you go with? I've heard good things about the recent Valve Art production.

I'm trying a quad of their KT-66 for my Bassman, and am thinking of their 2A3 for a "boat anchor" Hammond field coil amp modification project (4x 2A3 in push/pull, driven by a pair of 56, tube rectified with 5U4). It might make a kool amp for recording.

I have a question about biasing the YBA200. I just ordered mine and expect it in the next week and was looking around to see what mods people were doing. And I read at some point that someone had to take their head in to get it rebiased. I thought the YBA200 had autobiasing so that you wouldn't have to take it in. Is this true?

It is a fixed bias amp, so you do need to get it rebiased if you change the tubes.

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Ummm...yeh...bout that...on page three of the manual, point 13 would indicate that the autobiasing technology used makes it unnecessary re-biasing, and there's no need for using a matched set of tubes. I tried to cut and paste a quote from the .pdf, but got all kinds of weird images instead...but I'd go to the manual for specifics...that's it in a nutshell. No promises in regards to different types/ratings of tubes though.

I have a question about biasing the YBA200. I just ordered mine and expect it in the next week and was looking around to see what mods people were doing. And I read at some point that someone had to take their head in to get it rebiased. I thought the YBA200 had autobiasing so that you wouldn't have to take it in. Is this true?

Thanks

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It does have an autobiasing circuit. I had a single power tube go south in mine, and it was a simple swap; didn't have to buy a matched pair, or do anything manually.

Not sure how far that extends, though - if you were to decide to use a full set of different power tubes, I'd shoot an Email off to the Yorkville techs (they answer quickly) to make sure the autobiasing circuit can handle the change. If it can't, you might have to bring it in for a minor modification, such as a resistor change.

This will be interesting, I PMed TB Brent a few weeks ago and he said that his tech had to re-bias his yba200 for the kt88s, and that his tube swap made little difference in headroom, so I havent done it to mine.

The schematic shows couple of zener diodes used to set the bias, and the rev listing of the schematic shows a change in those diodes, so yorkville has played with the bias - so it seems the only way to change that bias is to swap out or piggyback one of those diodes.

Also, one of Brents (I hope he doesnt mind me quoting his posts) inital posts about the yba200 said that the YV eng saw about 50 more watts with the kt88s, and they need an increase of 5 volts in the bias.

I feel the amp is what it is, lots of tone and ways to dial in and change that tone, give it good speakers and IMHO it holds it own in loudness and character.